they want to know what happened and why they didn't stop these guns from leaving the united states and ending up in this, in these crimes. >> reporter: spanish-language network univision and fox news obtained a list of 100,000 weapons recovered in mexico and compared those serial numbers with the 2,000 guns sold in fast and furious. nearly two dozen matched, connecting an untold number of injuries and fatalities to the u.s. program. [speaking spanish] >> reporter: this woman lost two sons to fast and furious guns. >> they feel helpless. they don't know what to do, and we interviewed one of them, and they said, who's going to pay for this? >> reporter: it could be the u.s. government. >> the people can go and sue in the united states with the support of american lawyers, and that will be a very interesting development certainly. >> reporter: for its part, the mexican government has remained largely silent, unwilling to criticize its northern leader. >> our political elite is only worried about obtaining the next position, and the benefits they obtain from being in politics. >> reporter: